The objeective of this multicenter, open-label trial is to gain additional experience with topiramate among patients with infantile spasms, and to obtain a descriptive comparison of infantile spasm-free rates among cryptogenic/idiopathic, and symptomatic types of infantile spasms. A further objective is to identify an effective dose and the appropriate rate of titration of topiramate in subjects with infantile spasms. In addition, topiramate plasma levels associated with absence of infantile spasms will be assessed.